U.S. Pat. No. 4,663,725, which is assigned to the same assignee as the present application, discloses the use of microprocessor based transport refrigeration control for use with a refrigerated container, with the refrigerant compressor being driven by an electric motor. This patent is directed primarily to the use of a microprocessor to operate the various components of the refrigeration system according to predetermined algorithms, and to detect and record faults which occur during the operation thereof.
U.S. Pat. No. 4,918,932, which is assigned to the same assignee as the present application, discloses the use of a microprocessor to determine average error between an operator selected set point temperature and the temperature of a space to be conditioned, using the outputs of return air and discharge air sensors, and the use the average error in the determination of an error signal which modulates the capacity of the system.
While these patents ably utilize the capabilities of a microprocessor during the operation of a transport refrigeration system, it would be desirable, and it is an object of the present invention, to expand the use of the microprocessor which operates the unit, enabling it to aid in the test of the unit at the time of manufacture as well as providing unique features in pre-trip diagnostics which the operator puts the unit through prior to leaving a terminal with a new load.